1. Field of the Invention:
This invention relates to a mimeographic printing machine having a rotary cylindrical drum, and more particularly to a mimeographic printing machine having a paper sheet discharge mechanism for discharging by a peeling claw a paper sheet after printed.
2. Description of the Related Art
As shown in FIGS. 7 and 8 of the accompanying drawings, a mimeographic printing machine is currently known which includes a rotary cylindrical drum 102 for supporting on its outer circumferential surface a stencil 101 whose one end is gripped by a clamp 100. In this type of conventional machine, an ink supply means is located inside the cylindrical drum 102. During printing, ink supplied from the ink supply means passes through pores of the stencil 101 and then is transferred to a paper sheet 103 which is supplied on the surface of the stencil 101.
For discharging a paper sheet upon completion of printing, the above-mentioned mimeographic printing machine is equipped with a paper sheet discharging mechanism including a peeling claw 104 located adjacent to the cylindrical drum 102. In use, a non-printed portion of the printed paper sheet 103 is peeled by the peeling claw 104 from the surface of the stencil 101. The peeled paper sheet 103 is then attracted to an endless belt 106 by a suction device 105 having a suction fan, and is conveyed on the endless belt 106 toward a discharge tray.
The peeling claw 104 is equipped so as to prevent such a phenomenon, in which the paper sheet 103 after printed remains stuck on the surface of the cylindrical drum 102 due to viscosity of ink on the stencil 101 and is not conveyed to the discharge tray. The peeling claw 104 is therefore indispensable in an automatic paper sheet discharge mechanism for the mimeographic printing machine. The peeling claw 104 repeatedly comes into contact with and out of contact with the surface of the cylindrical drum 102 in synchronization with the rotation of the cylindrical drum 102. Specifically, at a paper sheet discharging position, the peeling claw 104 is advanced into a gap between a leading end of the paper sheet 103 and the stencil 101, thereby peeling the printed paper sheets 103 in succession during printing.
When peeling the printed paper sheet from the cylindrical drum by the peeling claw, it is however mechanically difficult to have the peeling claw 104 advanced reliably into the gap between the stencil 101 and the leading end of the paper sheet 103, as shown in FIG. 8. Specifically, the peeling claw sometimes fails to advance into the above-mentioned gap due to factors such as a kind of paper sheets, viscosity of ink, or printing speed. In such a case, the paper sheet would be folded and enter into a gap between the cylindrical drum and the peeling claw, or would be damaged by the peeling claw.